How to plot bed expansion in Ansys Fluent ?

 I have simulated unsteady fluidized bed at different superficial velocities and got result. now i want to plot a graph of expansion of bed vs superficial velocity. does fluent contain any option (xy plot) ?

Fluent itself doesn't have a dedicated function to directly plot bed expansion vs. superficial velocity. However, you can achieve this by utilizing built-in features and potentially a User Defined Function (UDF) depending on your approach. Here are two methods you can consider:

Method 1: Using Derived Variables and XY Plots

1. Monitor Bed Height: Use a report or monitor to track the average height of the fluidized bed during the simulation at each superficial velocity. You can achieve this by:

   • Volume Fraction Integration: Define a virtual box encompassing the bed and integrate the solid phase volume fraction (alpha_s) across its height. The integral value will be proportional to the bed height.
   • Interface Tracking (Optional): If the interface between the dense and dilute phases is well-defined, you can track the location of this interface to determine the bed height. This might require a UDF for more complex scenarios.

2. Calculate Expansion Ratio: After obtaining the bed height at each superficial velocity, calculate the bed expansion ratio. This is typically defined as the ratio between the expanded bed height (during fluidization) and the initial bed height (before fluidization).

3. XY Plot: Create an XY plot in Fluent. On the X-axis, plot the superficial velocity and on the Y-axis, plot the calculated bed expansion ratio. This will visualize the behavior of the bed expansion with changes in velocity.

Method 2: Using User Defined Function (UDF)

This method offers more flexibility but requires some programming knowledge in C. Here's the general idea:

1. Develop a UDF that calculates the bed height using a similar approach as outlined in Method 1 (volume or interface tracking).

2. The UDF can then store the calculated bed height and the corresponding superficial velocity in user-defined memory (UDM) locations.

3. After the simulation, use a report or define a custom function to access the UDM locations and calculate the bed expansion ratio at each superficial velocity.

4. Finally, create an XY plot as described in Method 1.

Choosing the Right Method:

• Method 1 is simpler and doesn't require coding. However, it might need additional configuration based on your specific bed geometry and simulation setup.
• Method 2 offers more control over the calculation and can handle complex scenarios. However, it requires UDF development which might be more challenging.

Additional Tips:

• Ensure consistency in how you define and measure the bed height across different simulations.
• Consider averaging the bed height data over a period of stable fluidization to minimize the impact of transient fluctuations.
• Consult Fluent documentation and online resources for detailed information on volume fraction integration and UDF development.

By applying these methods, you can create the desired plot visualizing the relationship between bed expansion and superficial velocity in your fluidized bed simulations.